AB0196 ABATACEPT VERSUS HYDROXYCHLOROQUINE IN PALINDROMIC RHEUMATISM: A MULTICENTER RANDOMIZED CLINICAL TRIAL (PALABA STUDY): TRIAL DESIGN AND PATIENTS CHARACTERISTICS
Authors: B. Frade-Sosa, R. Morlà, L. Tobalina, C. Perez-Garcia, I. Haro, R. Sanmartí
Journal: Annals of the Rheumatic Diseases (2022)

Background Many patients with palindromic rheumatism (PR), mainly those with positive autoantibodies, evolve to rheumatoid arthritis (RA). Management of PR is empirical, and hydroxychloroquine (HCQ) is the most used antirheumatic drug. Abatacept (ABA) has been investigated in preclinical RA with good results. There are no randomized clinical trials in PR. Objectives To present the design of a randomized clinical trial in PR (PALABA study). To describe the characteristics of the patients at study entry. The main objective is to test the hypothesis that ABA can reduce the progression of RA in seropositive (ACPA+ and/or RF+) PR patients in comparison with HCQ. Methods Phase IV multicenter open label randomized controlled clinical trial with 42 months duration. The enrollment period was 18 months and the open randomized period 24 months. Fourteen spanish centers were included. The sample size was 70 patients (35 per arm). ABA sc 125 mg/week first year, 125 mg eow second year and HCQ oral 5mg/Kg daily were administered, both therapies in monotherapy. The main inclusion criteria were age &gt;18 years with PR according to Guerne and Weissman modified criteria and disease evolution &gt;3 and &lt;36 months. Positive ACPA (ELISA or chemiluminescence (CCP2) and/or RF tests are required. Patients with arthritis in ≥1 joint &gt;1 week at baseline, with criteria of other rheumatic diseases, radiographic erosions or previous antirheumatic therapy with synthetic DMARDS were excluded. The main outcome measure is achievement of RA classification criteria (EULAR/ACR 2010) at any time during the 24-month follow-up. Secondary outcomes were the number and intensity of joint attacks, adverse events, and effects on serum ACPA and anti-carbamylated antibodies at 0,3,12,24 months of follow-up. STATISTICS: Modified Full Analysis Set and Per Protocol Population analysis. Results Patient one was included in June 2018. The inclusion period has been extended until April 2022 due to low recruitment rates, partly due to the COVID-19 pandemic. As of 15 Jan 2022, 51 patients have been randomized and 49 (37F/12M) have received at least one drug dose. The mean onset of symptoms was 9.9±6.3 months. In 22 patients the follow-up time was greater than 12 months. RF and ACPA (CCP2) were positive in 81.6% and 89.8% of patients respectively; 24 patients were included in the ABA arm and 25 in the HCQ arm. Seven patients withdrew from the study during follow-up due to: progression to RA (n=3), adverse events (n=2) and other reasons (n=2). The demographic, clinical and laboratory characteristics of PR patients at study entry are shown in Table 1. No significant differences in patients’ characteristics between arms were observed at enrollment except a higher prevalence of CCP2 in the HCQ arm. Table 1 Baseline demographic, clinical and laboratory characteristics at study entry Age, mean (sd) 49.6 (11.2 ) 49.8 (12.0 ) 49.4 (10.7 ) NS Female, n (%) 37 (75.5 ) 19 (79.2 ) 18 (72 ) NS Body mass index, mean (sd) 27.(5.7 ) 26.6 (5.5 ) 27.4 (5.9 ) NS Month of symptom duration, mean (sd) 9.9 (6.3 ) 9.8 (6.8 ) 9.9 (5.9 ) NS Current Smokers, mean (sd) 15 (30.6 ) 6 (25 ) 9 (36 ) NS Number attacks 6 months before inclusion, mean (sd) 4.65 (4.07 ) 4.24 (2.78 ) 5.0 (5.0 ) NS PIP/MCP involvement n (%) 35 (71.4 ) 16 (66.7 ) 19 (76 ) NS Wrist involvement, n (%) 32 (65.3 ) 17 (70.8 ) 15 (60.0 ) NS Involvement of other joints, n (%) 30 (61.2 ) 14 (58.3 ) 16 (64.0 ) NS ESR (mm), mean (sd) 20.71 (16.8 ) 23.13 (18.8 ) 18.30 (14.8 ) NS RF positive, n (%) 40 (81.6 ) 19 (79.2 ) 21 (84 ) NS ACPA (CCP2) positive, n (%) 44 (89.8 ) 19 (79.2 ) 25 (100 ) 0.022 PIP: proximal interphalangeal MCP: metacarpophalangeal Conclusion We present the design of the first randomized clinical trial in PR of the efficacy of antirheumatic drugs (ABA vs HCQ) to avoid progression towards RA in patients with a high risk (recent onset PR and positive autoantibody status) of persistent arthritis. The characteristics of patients included until now are similar to those reported in recent onset PR. Acknowledgements PALABA study investigators: Beatriz Frade-Sosa, Rosa Maria Morlà, Lola Tobalina, Maria López-Lasanta, Helena Borrell, Georgina Salvador, Andrea M Cuervo, Noemí Busquets, Eduard Graell, Carolina Pérez- García, Luciano Pocino, Delia Reina, Oscar Camacho, Hector Corominas Ana M Millan. Miquel Sala, Sonia Castell, Eduardo Kanterewicz, Josep R. Rodriguez Cros, Alejandro Escudero, Usansolo Irati, José Francisco Garcia, Francisco Javier Toro, Natividad Oreiro, Alejandro Olivé, Maria J Gómara, Cristina García-Moreno, Isabel Haro and Raimon Sanmarti. Disclosure of Interests Beatriz Frade-Sosa: None declared, Rosa Morlà: None declared, Lola Tobalina: None declared, Carolina Perez-Garcia: None declared, Isabel Haro: None declared, Raimón Sanmartí Speakers bureau: received speaker honorariafrom Abbvie, BMS, Gebro-Pharma, Lilly, MSD, Pfizer, Sanofi and Roche, Grant/research support from: investigation grants from Abbvie, BMS, Gebro-Pharma, Lilly, MSD, Pfizer, Sanofi and Roche